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Hallyn" , keyrings@vger.kernel.org, Jann Horn , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, David Howells , Paul Moore , James Morris Subject: Re: [RFC PATCH 0/2] keys: Address lookup_user_key() mutability Message-ID: References: <20260924055521.1981957-1-jarkko@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Oct 05, 2026 at 09:46:41PM +0300, Jarkko Sakkinen wrote: > On Mon, Oct 05, 2026 at 08:09:24AM -0500, Serge E. Hallyn wrote: > > On Sun, Oct 04, 2026 at 08:54:06PM +0300, Jarkko Sakkinen wrote: > > > On Thu, Sep 24, 2026 at 08:55:16AM +0300, Jarkko Sakkinen wrote: > > > > The main objective in these patches is to remove to unneeded mutability > > > > from key look ups. It does harm and brings no value so it is pretty obvious > > > > to me that addressing this harmful behaviour is what we should do. > > > > > > > > I based the first patch on what Jann suggested in [1]. Nothing too clever here > > > > and I'm ofc open for further suggestions. > > > > > > > > [1] https://lore.kernel.org/keyrings/CAG48ez0XjVSR=M--UBauTm8sJuc+ZbhKzaPa3a6wrSVHyoKevw@mail.gmail.com/ > > > > > > > > Jarkko Sakkinen (2): > > > > keys: Return user session keyring on lookup > > > > keys: Reject keyring creation with overridden credentials > > > > > > > > Documentation/security/keys/core.rst | 7 ++- > > > > security/keys/process_keys.c | 65 +++++++++++++++------------- > > > > 2 files changed, 40 insertions(+), 32 deletions(-) > > > > > > > > -- > > > > 2.47.3 > > > > > > > > > > So.. should I move forward to with non-RFC v2? > > > > Patch 2 absolutely makes sense, "doc, it hurts when I do this", "don't do > > that then." > > > > Regarding patch 1, that seems like quite a change in behavior, right? I > > don't see any docs or comments that promise the current behavior, but > > has any userspace or subsystem come to depend on it? I guess that, if so, > > then it just has to create a link to the user session keyring like pam > > (according to what I've read) does? > > Thanks a lot of responding. > > I fully agree with you but I'd need help for evaluating things further. > > 1/2 based on Jann's email about the topic and my interpretation of the > suggestion. I neither used brains nor AI for this and consider the patch > merely as a conversation starter (and what a great success it was on doing > that) :-) :) > All feedback is good feedback at this point. I need supporting code to > remember/recall later on so at least this serves that purpose. > > Br, Jarkko I've been staring at the before and after code for a bit now. It does even more than I was thinking :) But I was trying to detail the changed behavior (from userspace's pov), and after several attempts, it seems maybe there actually isn't any. Q: is there any path whereby the ``` else if (test_bit(KEY_FLAG_UID_KEYRING, &ctx.cred->session_keyring->flags) && lflags & KEY_LOOKUP_CREATE) { ``` case can still happen? Or was this the only place where we installed the user_session keyring as session keyring, so that we can drop this branch?